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Dehydroalanine derived from cysteine is a common post‐translational modification in human serum albumin
Author(s) -
BarOr Raphael,
Rael Leonard T.,
BarOr David
Publication year - 2008
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3421
Subject(s) - chemistry , dehydroalanine , human serum albumin , cysteine , trypsin , chromatography , mass spectrometry , tandem mass spectrometry , serum albumin , fragmentation (computing) , peptide , residue (chemistry) , molecular mass , biochemistry , enzyme , computer science , operating system
Abstract The conversion of a cysteine residue into dehydroalanine (DHA) in proteins was previously described. This post‐translational modification (PTM) can be generated artificially as a result of heat and an alkaline environment. The presence of this PTM on human serum albumin (HSA) in plasma collected from healthy volunteers and critically ill patients as well as in commercially available HSA was studied. Using liquid chromatography/mass spectrometry (LC/MS) and matrix‐assisted laser desorption/ionization tandem mass spectrometry (MALDI‐MS/MS) methods, a fragment containing DHA was identified in the trypsin digest of commercial HSA and isolated HSA from plasma. The sequence (RPC*FSALEVDETYVPK) corresponded to the expected molecular mass and fragmentation pattern of a tryptic peptide of HSA where the cysteine residue (cys487) was modified to DHA. The presence of this common PTM of HSA has potential effects on ligand binding to HSA, plasma clearance of this oxidized form of HSA, protein‐protein interactions, and oxidation‐reduction potential. Copyright © 2008 John Wiley & Sons, Ltd.